(CNN) – The battle for U.S. Senate in Massachusetts, which seemed over the summer to be the nation's most civil political race, has morphed into one of the ugliest.
In just the last three days, dueling attack ads have reignited the debate over Elizabeth Warren's Native American heritage, with Sen. Scott Brown, Warren's Republican rival, suggesting in his spot that Warren is untrustworthy.
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Warren fired back, producing an ad claiming Brown was attacking her family.
On Tuesday, videotape surfaced of Brown staffers making offensive gestures at a Warren rally that seemed to mock Native Americans. The principal chief of the Cherokee Nation called the "war whoops" and "tomahawk chops" "offensive and downright racist," saying the actions "perpetuate negative stereotypes and continue to minimize and degrade all native peoples."
Asked about the tape Tuesday at a press availability at Boston's South Station, Brown said he hadn't seen the footage but did not support the actions as described by reporters.
"That's not something I condone. It's certainly something that if I am aware of it, I'll tell that member to never do it again," Brown said, before launching into an attack on Warren's claims to Native American heritage.
It's all a sudden move to the low road for two candidates who seemed determined earlier in the race to stick to the issues. Both signed a pledge in January calling for super PACs and other third party groups to stay out of their contest, hoping to keep focused on issues that affect the Bay State. The campaigns also promised not to coordinate with any groups planning to launch "sham ads" during the course of the campaign.
READ MORE: Elizabeth Warren vs. Scott Brown: Priciest race this year
Brown stuck largely to a message of bipartisanship on the stump and in interviews, keenly aware of Massachusetts' moderate Republican base he hopes to win in November.
In an election year when most Republicans running for re-election boast about their votes blocking President Barack Obama's agenda, Brown has bragged about helping the Democratic incumbent.
"I can name a litany of Democratic-sponsored bills that never would have passed had it not been for me," Brown told CNN in July. "The president had called me. The vice president calls me. Secretary [of State Hillary] Clinton calls me for my vote all the time."
That claim was followed up with a fact-check in the Boston Globe, which reported Clinton and Brown had spoken twice by phone. He spoke with Biden and Obama each once by phone, but has held in-person meetings more frequently with the president and vice president.
At the beginning of September, Brown produced an ad showing him shaking hands with Obama.
"Good job," the president is seen saying in the spot.
Warren, for her part, focused largely on her record as a consumer advocate, rather than on Brown, using her speeches to tout her record as the brains behind the new Bureau of Consumer Protection.
At the Democratic National Convention, Warren delivered a strident speech that brought a packed convention arena to its feet in thunderous appreciation – but didn't mention her rival by name.
"Americans are fighters. We are tough, resourceful and creative. If we have the chance to fight on a level playing field – where everyone pays a fair share and everyone has a real shot – then no one can stop us," Warren said.
Until Warren's prime-time address at the DNC, the race remained close. But a pair of surveys after the speech showed the Democratic candidate pulling ahead of Brown, 48%-44% in a Suffolk University/7News poll and 50%-44% in a Western New England University poll.
And thus the onslaught began, with Brown launching full tilt into an attack on Warren's claims to Native American ancestry.
READ MORE: Elizabeth Warren: Is she or isn't she Native American?
Last week, Brown opened an hour-long debate with the issue, claiming Warren wasn't being totally transparent about why she was listed at Native American when she was a professor at Harvard Law School.
"Professor Warren claimed that she was a Native American, a person of color and as you can see, she's not," Brown said. He repeated his call for his opponent to release records showing whether she had claimed Native American heritage on job applications.
"When you are a U.S. Senator, you have to pass a test and that's one of character and honesty and truthfulness. I believe and others believe she's failed that test," Brown said.
That attack was followed by the television spot, which Warren rebutted with a spot of her own.
"Let me be clear. I never asked for or never got any benefit because of my heritage," she says, addressing Brown's central concern. "The people who hired me have all said they didn't even know about it."
"Scott Brown can continue attacking my family, but I'm going to keep fighting for yours," the former Obama administration official concludes.
On Wednesday, Brown made another attempt at cracking Warren's image as a crusader for the middle class, addressing a letter to his rival asking her to disclose her outside legal work while she was working as a professor at Harvard Law School.
Brown cites reports that Warren provided legal counsel to Travelers Insurance and LTV Steel while she was a professor, which Brown claims in his letter "is at odds with the image you portray on the campaign trail fighting for the middle class and the little guy."
"During this campaign, you have accused others of siding with big corporations," the GOP senator concludes. "As it turns out, you are the only candidate in this race who has stood on the side of large corporate interests over the middle class."
At a press conference in Boston Wednesday, Warren countered Brown's claims by pointing out her rival has "never released the name of a single client," according to the Boston Herald.
"I think what he's trying very hard to do is not talk about his voting record. So let's keep count, so far he's come after my family, he's come after my teaching, he's come after when I've gone to the U.S. Supreme Court," she said.
CNN's Ashley Killough, Dana Bash and Alison Harding contributed to this report.
The article mentioned "dueling attack ads" but the attack seems pretty one sided and racially motivated on Brown's part. Like millions of families she has been told stories of having Native American blood that may or may not be true. It's completely irrelevant to her qualifications for the job at hand though. These attacks are pretty desperate.
Stick a fork in Scott Brown, he's done.
"Truth Hurts" – What really hurts is that your candidate Scott Brown is about as lowly a snake as Mitt Romney.
You forget, Brown came in on a wave supported by and pandering to the TEA Party. After his election, he told his partisan supporters to "Take a ride" and ditched the TEA party like a hot potato.
Brown professed himself to be a "Conservative" and voted against women's interests (for every anti-abortion bill) before being caught up in the Paul Ryan / Tod Akin "legitimate rape" scandal. After that he abandoned the Republicans altogether and all of the sudden became a RINO Liberal!
So Brown server in the military? Dig Deal. So did McCain, and Alan West. It doesn't make them any less imbecile with their stupidity.
Sorry bud, your candidate
Good grief already, you repubs can sure sling it, but you will see in nov. how badly out of touch your party is, rich are the minority, poor are the masses, block votes, spew lies, organize your defensive arguements all you want. when the vote comes in, you'll still be in denial, the majority does not like the koch brothers, or grover, or any super rich, we know how they got that way. rich are not happy merely being pampered, now they want to force theier ideaology on us. we will try to help you this nov.6. just watch your party go down in masses.see ya
Why should Warren's race/cultural affiliation matter one whit? It is the GOP so fixated on race? They are sick on it.
He was such a successful male model , he will have such a bright future as a lobbyist for Wall St on K street.
Looks like its over Mr Tea Bagger Brown your toast. Really war whoops WFT were you thinking oh I forgot you don't know how to use that thing you call a brain. What next white robes and pointed hoods?
What does her heritage have to do with her qualifications of a job!? Sounds like the same old republican fear mongering politics........time is moving forward..! When will these clowns seized to exist..!
Scott Brown's political strategy is in case of emergency of campaign spiraling out of control, poll numbers trending down, favorability numbers going up, is to break glass and remove race card and play.
Seriously- have you ever tried anger management? That nasty little world you've created for yourself isn't a nice place-nor very real.
Mr Tea Bagger you can start by firing your staff who are in the video making war whoops. Nice try on saying you did not have a hand in this.
One more democrat in the big house, when will repubs learn, YOU DO NOT SHARE THE VIEWS OF THE MAJORITY, do yourselves a favor and shut up already, dont you guys have anyone normal to bounce theese things off first?. wildly out of touch!